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Home charging dropping to 16A

pdk42

Active Member
Jul 17, 2019
1,070
1,048
Leamington
I'll preface all this by saying that I got my car yesterday and last night was the first attempt at home charging.

However, even before last night, my road to home charging has been a bit rocky. I'm now on my second charger after the initial Rolec just stubbornly refused to do anything when I tested it with a BMW i3 loaner. So I've now got an Elvi which has its own WiFi connection issues but seems to at least work as a dumb charger.

I say "seems" since I've got problems with charge current. Charging starts fine at 32A and a voltage of 225V (which drops from 240V as the current ramps up). That voltage is a bit low I think, but it's giving 28 miles/hr charge. Happy with that. I've watched it for 10-15 mins and all seems fine.

However, checking it a while later (an hour or so) I found that the charge current had dropped back to 16A and seemingly stays there. The car says 16A/16A. I reset everything and started again - same result, starting at 32A and some time later dropping back to 16A.

So, a few questions for you experienced Tesla guys:

- Is it the car or the charger that's throttling the current?

- Is it likely that the throttling is because the voltage hadms dropped too far?

- Will it likely go back up at some point?

Any ideas would be greatly appreciated! 16A won't give me the range I really need.
 

booyaka76

Member
Aug 19, 2019
282
227
Ayrshire
I've had the same issues with my Rolec,

Jumps to 32A at the start - then drops back to 16A. Did that for a few days, now tripping the RCD.

It's getting swapped out for a new unit on Monday...

Whether it's the same issue is hard to say, but even with the 13A UMC plug, it seems to charge for 10/20/30 minutes, then stop charging for no apparent reason.

If the new Rolec gets fitted and has the same issues, then I think the only thing left is something in the car is the problem.

Video here of my issues.

 

pdk42

Active Member
Jul 17, 2019
1,070
1,048
Leamington
Hmm - that's not quite the same as the scenario I have. This is what happened with me - blow by blow (excuse the day-in-the-life activities!):

- I get home with the new car and plug it in.
- I press "start charging" and the display indicates 32A/32A and voltage about 225V
- I watched it for about 10 mins and it stays like this. 28 miles/hr. Great ! Happy bunny!
- I stop the charging and set it for a 1am start (economy 7).
- I go to bed
- I wake up for some reason about 1:30 so think I'll pop down and take a look
- Phone app shows 16A/16A !
- I go out in the pissing rain in my jimmy jammies and reboot the charger.
- Car starts charging again at 32A/32A
- I go back to bed
- I get up at 7 and the phone says 16A/16A again
- I restart it (again in my jimmy jammies) - charge goes back to 32A/32A
- I have a shower etc and go down for breakfast (maybe 20 mins)
- Car is still charging at 32A/32A.

I'm sort of guessing that it's a supply issue and the car is pulling the current back as a precaution.

I'm going to try reducing the charging current on my own charger to see if that helps (in case the voltage is dropping too much) and then will see if I can try a colleague's charger - who also has a Model 3.

In the meantime - can I ask that people charging at home at 32A tell us what voltage is showing?
 

Marc Roberts

Member
Jul 9, 2019
576
383
UK
I'm getting a similar thing recently with my PodPoint. The car will randomly be only drawing 18A/30A. The car is set to 30A, and it knows it, but for some reason is only drawing 18A. It sometimes charges like that for ages, sometimes it ramps back to 30A by itself.

It isn't a huge problem charging at 4kW, just weird...
 

smeg9

Member
Sep 24, 2019
13
10
UK
How heavy duty is the wiring? Is any of it getting too hot after a period of time maybe?

Average voltage home charging at 32A is 233.22V - Teslafi is really good showing this, as well as drawing graphs of the charge over time (Volts and Amps)

At work we I've used Centrica 7kW charging points, the voltage averages 226.11V but these chargers seem to max out at 16A not 32A.... One was stuck at 15A, peaking for just 1 data point at 16A when there was a slight increase in voltage..
 

pdk42

Active Member
Jul 17, 2019
1,070
1,048
Leamington
How heavy duty is the wiring? Is any of it getting too hot after a period of time maybe?

Average voltage home charging at 32A is 233.22V - Teslafi is really good showing this, as well as drawing graphs of the charge over time (Volts and Amps)

At work we I've used Centrica 7kW charging points, the voltage averages 226.11V but these chargers seem to max out at 16A not 32A.... One was stuck at 15A, peaking for just 1 data point at 16A when there was a slight increase in voltage..
Thanks, I must get Teslafi. Will that show me when it dropped to 16/16?
 

ivangr

Member
Jul 22, 2019
198
124
dunfermline
my pod-point gets stuck at 14 amps. i have a ticket open.

wrt varying charge rates. there is a bit in the model 3 manual that says the car will turn down charging if the voltage is inconsistent, i think
 

pdk42

Active Member
Jul 17, 2019
1,070
1,048
Leamington
I posted a similar question over on the Facebook Tesla Uk Owners Group. Seems others have had similar issues with the Elvi unit. I think I'll put a 32A commando socket in and see what happens with that. Cut out the charger from the equation.
 

pdk42

Active Member
Jul 17, 2019
1,070
1,048
Leamington
A quick update for those interested. I got a call from a very helpful guy at EVBox (who make the Elvi). It looks like the installer has installed an old rev of the Elvi and there are known issues with falling back to 16A charging (maybe overheating?). He could also see that the unit was registered to another account (which explains why I couldn't add it to mine!) and was somewhat annoyed that the installer left without doing basic connectivity and config. Anyhow, I'll hopefully get a replacement from EVBox, but we'll see.

Stratford Energy who installed it have been responsive and friendly, but in the end they installed a Rolec back in August that they couldn't get to work (after four weeks of trying) and have now given me some old Elvi that was was probably hanging around in the back of the warehouse after someone returned it - and then didn't even do the installation properly. Not impressed!
 
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Roy W.

Battery running low...
Jun 3, 2019
2,307
2,319
Derby, UK
Stratford Energy who installed it have been responsive and friendly, but in the end they installed a Rolec back in August that they couldn't get to work (after four weeks of trying) and have now given me some old Elvi that was was probably hanging around in the back of the warehouse after someone returned it - and then didn't even do the installation properly. Not impressed!
If in doubt, fob the customer off :)
 

M3winEVwin

Member
Jun 3, 2019
24
8
Sunny Sussex
Well, I am having similar issue. Had my 3 for a month now and charged it at home with a ROLEC. Never had any issue charging until tonight... Usually I got 7kW 32/32A but tonight it stop at 4kW 16/32A. The only explanation I found is in the owner manual:

Note: If Model 3 is charging and detects unexpected fluctuations in input power, the charging current is automatically reduced by 25%. For example, a 40 amp current is reduced to 30 amps. This automatic current reduction increases robustness and safety in situations when an external problem exists (for example, a home wiring system, receptacle, adapter or cord is unable to meet its rated current capacity). As a precaution, when Model 3 automatically reduces current, it saves the reduced current at the charging location. Although you can manually increase it, Tesla recommends charging at the lower current until the underlying problem is resolved and the charging location can provide consistent power.

However I wonder if it could be linked to the latest software update? I recently updated a second version of V10
 

pdk42

Active Member
Jul 17, 2019
1,070
1,048
Leamington
My problem was due to the charger. I eventually got a replacement unit and since then all had been fine (but keeping my fingers crossed)
 

M3winEVwin

Member
Jun 3, 2019
24
8
Sunny Sussex
Understood your problem is slightly different but if this drop is happening to many people then it might be something else than the charger (for my case).
It worked fine for a month so it is a bit strange. But a fault may have triggered this situation..
 

WannabeOwner

Well-Known Member
Nov 2, 2015
5,758
2,896
Suffolk, UK
I must get Teslafi. Will that show me when it dropped to 16/16?

yes :)

the graph displays per minute the amperage and voltage so you'd be able to pin point the timing.

There is also a "Raw Data" data grid display (on HELP menu). That shows various data elements (you can choose from a list) which can help with this sort of issue.

A referral code (at time of registration) will increase your trial from 2 weeks to a month - probably enough time to get this sorted out. If you want mine drop me a PM, and I'll also send you a "suggestions sheet" which I have evolved over time for other people who wanted a TeslaFi referral
 

pdk42

Active Member
Jul 17, 2019
1,070
1,048
Leamington
yes :)



There is also a "Raw Data" data grid display (on HELP menu). That shows various data elements (you can choose from a list) which can help with this sort of issue.

A referral code (at time of registration) will increase your trial from 2 weeks to a month - probably enough time to get this sorted out. If you want mine drop me a PM, and I'll also send you a "suggestions sheet" which I have evolved over time for other people who wanted a TeslaFi referral
I took out a Teslafi trial. It's a great piece of software. UI could do with being updated so that it adapts to a mobile phone browser (or perhaps adding a mobile app front end), but it's got great functionality and seems really stable.

I'm still a little nervous about security though since it's got a token to access the car and it stores all my travel details including my home location so if the site got compromised, it would be a car thief's bonanza.

However, I'm thinking I'll take a subscription anyhow. I think any site attack would be publicised quickly and I could cancel the token.

Anyhow - I'd be very grateful for your suggestions sheet - it's too late now for the referral. Thanks!
 

arg

Supporting Member
Aug 22, 2012
1,806
1,797
Cambridge, UK
- Phone app shows 16A/16A !

Various other people with Model3s have been suffering reduced charging speed issues, but it's not clear that all these are the same issue.

In theory the "16/16A" means that the chargepoint is only offering 16A (2nd number) and the car is taking everything it is offered; if the car had decided for whatever reason to reduce the current, it should be showing 16/32A. So this does suggest an issue with the chargepoint.

UK supply voltage is 230+10%/-6%, so anything from 216V to 253V at the meter is acceptable, and a further 5% drop (max) is allowed within your own wiring, so the lowest possible voltage without a defect is 205V. So your 226V doesn't sound like a low supply voltage issue, though if it really dropped from precisely 240 down to 226 just as it started charging (and presumably went back up to something like 233V when the current dropped to 16A?) then that's a bit more voltage drop than I would expect, albeit not enough to definitely point at a problem.
 

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